Refrigerating method and apparatus



Sept- 4, 1934- D. N. cRosTHwAlT, .1R4 1,972,705

REFRIGERATING METHOD AND APPARATUS Filed Sept. 7, 1933 2 Sheets-Sheet l B5 i// j? 30 if Inde nto-T Sept. 4, 1934. D. N. cRosTHwAlT, JR

REFRIGERATING METHOD AND APPARATUS Filed Sept. 7, 1935 2 Sheets-Sheet 2 Patented Sept. 4, 1934 UNITED STATES PATENT OFFICE 16 Claims.

This invention relates to a new and improved refrigerating method and apparatus, and more particularly to certain improvements in a closed cycle refrigerating system of the type in which a jet of relatively high pressure vaporized refrigerant is utilized to create the low vaporizing pressure in the evaporator and to withdraw 10W pressure vaporized refrigerant from the evaporator, compress it, and return it to the condenser. This invention is in some respects an improvement on the system disclosed and claimed in my copending application, Serial' No. 440,519, filed March 31, 1930.

Briefly described, this improved closed circulation system comprises a generator in which the liquid refrigerant is vaporized by heat and forced under relatively high pressure through a jet exhauster and compressor which function to withdraw the low pressure vaporized refrigerant from.

the evaporator or refrigerating device. The mixed vaporized refrigerant from the jet exhauster (comprising the original power stream from the jet .with its pressure now somewhat reduced, and the low pressure refrigerant from the evaporator. which has been compressed by the jet compressor), are passed through a condenser, and the condensed refrigerant under this intermediate pressure is collected in a condensate receiver. A differential-pressure actuated valve is positioned in the original power stream line in advance of the jet compressor so as to insure a predetermined minimum pressure difference between the relatively high pressure vaporized refrigerant used as a power iluid,'and the intermediate pressure condensed refrigerant a portion of which is utilized in the refrigerating process. A portion of the condensed refrigerant in the receiver is permitted to pass through a ilow controller into the evaporator which is maintained at a lower pressure by the action of the jet exhauster. This condensed refrigerant vaporizes Within the evaporator to produce the refrigerating effect and withdraw heat from the materials or space to be refrigerated, and this low pressure vaporized refrigerant is drawn back and compressed by the jet compressor and returned into the condenser. The remainder of the condensed refrigerant collected in the receiver into which the condenser discharges is returned into the generator.

Several different alternative means, as herein:

after disclosed, may be provided for returning this condensed refrigerant against the higher pressure existing in the generator.

The principal object of this invention is to provide an improved refrigerating method and appa- (ol. ca -115) ratus such as briefly described hereinabove and disclosed more in detail in the specifications which follow.

Another object is to provide improved means for automatically maintaining a predetermined minimum pressure difference between the vaporized power refrigerant which flows through the jet compressor, and the pressure of the condensed refrigerant, that is the pressure against which the jet compressor discharges.

Another object is to provide an improved sealed refrigerating apparatus including few moving parts, in which the refrigerant may be operated under relatively low pressures, some of which may be less than atmospheric pressure. i

Another object is to provide a refrigerating system in which a single fluid serving both as a refrigerant and as a power fluid is circulated substantially continuously through a sealed system comprising a main power cycle and a'refrigerating cycle, portions of the two cycles coinciding.

Another object is to provide improved means for increasing the efficiency of the jet compressor.

Another object is to provide improved methods l and means for returning the condensed refrigerant to the generator.

Another object'is to provide an improved form of collecting apparatus for the condensed refrigerant, in which the pressure is alternatively varied to permit condensed refrigerant to flow thereinto by gravity from the condenser, and to flow therefrom by gravity into the generator.

Another object is to provide an improved form of fluid-pressure actuated pump for returning condensed refrigerant into the generator.

.Another object is to provide "an improved refrigerating system suitable for small domestic refrigeration units, which is simple and reliable,

and economical in operation.

Another object is to provide an improved refrigerating apparatus that will be self-starting and which will automatically operate continuously as long as lthe refrigerating action is de-V sired. .l

Numerous other objects and advantages .of this invention will be moreapparent from the following detail description of certain' approved forms of apparatus constructed and operating according to the principles of this invention.

In the accompanying drawings:

Fig. 1 is a Adiagrammatic view showing one form of the assembled refrigerating apparatus.

Fig.2 is a central longitudinal section through a preferred form of jet-compressor.

Fig. 3 is a detail elevation, partially broken away, showing a single-unit alternating receiver for returing condensed refrigerant to the generator. V

Fig. 4 is a diagrammatic assembly, similar to Fig. 1, showing a pumping mechanism for returning condensate to the generator.

Fig. 5 is a vertical central section showing one form of pump, as illustrated in elevation in Fig. 4.

Fig. 6 is a partial Vertical section showing a modified form of pump.

Fig. 7 is a partial vertical section other form of pump.

'I'he apparatus comprises a closed circulation system, which may be hermetically sealed, and which contains ,a suitable quantity of a single operating fluid which serveslboth as a power fluid and as a refrigerant. A great variety of suitable refrigerants may be used, of which water is the simplest example. Numerous other suitable refrigerants are well known in the art. It is only necessary` that the fluid be one which exists both in the liquid and gaseous states within the range of pressures and temperatures under which this system is operated. The system comprises a power loop or cycle anda refrigerating loop or cycle through which portions of the refrigerating fluid separately circulate, but a'considerable portion of each of the two cycles coincide with one another and the refrigerant circulates through this common portion as a single stream, and the same portion of the refrigerant may circulate at one time through one of the loops and at another time through the other -loop without disshowing antinction. l

condensate collector E, the reducing or expansion-va1ve`G,the evaporator H, the jet compressor C, and the condenser D, these elements being connected in series in the order named. It will be noted that 'that portion of the two cycles including the jet-compressor C, the condenser D, and the condensate'collector E, is common to the two loops or cycles.

It may herebe stated that under normal operating conditions the refrigerant will exist under three separate and distinct pressures in different portions of the circulating system. A relatively high pressure will exist in the generator A and that portion of thev supply piping extending to the pressure control valve B, or, when valve B is open to the inlet of, jet exhauster C. This high pressure will also exist at intervals in the alternating-receiver device F, as hereinafter described. A low vaporizing pressure will exist in that portion of the refrigerating cycle extending from the expansion valve G through the evaporator H and back to the compressor C. An intermediate pressure exists from the jet compressor C through the condenser D, condensate collector E and into the refrigerating cycle as far as the expansion valve G. 'I'his intermediate pressure will also exist in the receiver F at .certain times so that the condensate may drain thereinto by gravity.

The several constituent elements of the apparatus will now be described somewhat more in detail. The generator A is in the form of a'closed .3 and 4. At 5 is indicated a thermostat positioned in or adjacent the evaporator H so that the power circuit for the heater may be opened when a desired low temperature has been established in the refrigerating apparatus. At 6 is indicated a pressure-controller preferably of the quick-acting or snap action type positioned in the generator A so as to shut off the heater when a certain predetermined maximum pressure has been establishedin the generator and the high pressure side of the system.

The vaporized high pressure refrigerant flows through the pipe y'7 to the control valve B and thence through pipe 8 to the jet exhauster C. The valve B may be of well known type, including a cut-off valve within vthe casing 9 which is actuated to open or vclosed position bythe movements of a diaphragm within the casing 10. This diaphragm is subject on one side to the high pressure existing in the pipe line '7 and on the other side, through pipe 11, toithe intermediate pressure existing in the condenser and the condensate collector E. The valve is so balanced that when a certain minimum pressure difference is established between the high pressure refrigerant in pipe '1 and the intermediate pressure refrigerant in condensate collector E, the valve will open and permit` the high pressure vaporized refrigerant to ow into the jet exhauster C. If the pressure difference falls below this predetermined minimum, the valve B will automatically close so as to prevent an equalizing of the pressures in the generator and high pressure line, and in the jet compressor and condenser. Therefore the jet compressor cannot operate unless there is a sufficient pressure difference to insure a proper operation of the com-l l l heat exchange, and consequently a greater pres-v sure difference and a greater compression effect upon the gaseous refrigerant withdrawn from the evaporator. The compressor comprises a rather long tubular casing 12 provided with an inwardly extending annular flange or collar 13 at one end and an internally threaded portion 14 at the other end. The conduit 15 through which the lower pressure refrigerant is returned from the evaporator H is threaded into an Inlet nozzle 16 adjacent the discharge end of the casing. 'Ihe inletv nozzle member 17 for the power fluid vis provided with a large central collar member 18 exteriorly threaded to engagevwithin the internally threaded end portion 14 of the casing 12, and is provided'with a. connection 19 into which the supply pipe-8 is tted. This inlet nozzle member 17 is provided with a dischargenozzle 20 having a converging passage leading tothe discharge opening 21 which is located slightly beyond the minimum diameter of the passage, that is the discharge end of the nozzle preferably flares outwardly. A second nozzle member comprises a nozzle portion 22, a cylindrical shell 23 adapted to fit within the casing12, and a connecting annular web 24 provided with a circular series ofopenings or passageways 25. Similarly a third nozzle member comprises a nozzle portionO 26, a hollow cylindrical shell 27, and a connecting wall or web 28 provided with a circular series of openings 29. A greater number ,of nozzle members such as 22 and 26 could be used if desired in order to accomplish the desired compression and heat exchange effects. The delivery tube 30 comprises a cylindrical shell portion 31 adapted to be clamped between the flange 13 at one end of casing 12 and the inner end of cylindrical shell 27 of the adjacent nozzle member 26. The shell portion 31 is provided with an opening 32 adapted to register with the inlet pipe15 so as to establish communication with the chamber 33 about the discharge nozzle 26. The outlet end of delivery tube 30 is connected at 34 with the discharge pipe 35 leading into the condenserV D. The delivery tube 30 and the several nozzle members may be assembled in an obvious manner within y the casing 12, and suitable gasket members may be inserted between the members to insure fluidtight connections.v

The low pressure vaporized refrigerant from the evaporator H will be ,drawn through the pipe 15, provided with the check valve 36 opening toward the compressor, into the chamber 33. Some of lthis refrigerant will thence ow through openings 29 into the chamber 37 surrounding the nozzle 22, and some will ow through openings 25 into the chamber 38 surrounding the inlet nozzle 20. Upon the initial starting of the actuating jet, al lower pressure will exist in the chambers 33, 37 and 38 than in the inlet passage 39 through which the actuating jet is discharged, because the differential control valve B will-prevent ,the

actuating jet being started until a predetermined pressure difference has been established. Normally the pressure in the chambers 33, 37 and 38 will be substantially the low pressure existing in the evaporator H, whereas the pressure of the actuating fluid in inlet passage 39 will be substantially that existing in the generator A. The low pressure vapor introduced into chambers 33, 37 and 38 will also be at a much lower temperature than the actuating fluid entering through passage 39, even though the temperature of this low pressure refrigerant has been raised by the heat withdrawn incidental to the' refrigerating process in evaporator H. Consequently a heat exchange will occur between the actuating vapor and the low pressure refrigerant. The converging passages in the jet nozzles will be shaped to converge in proportion to the change in specific volume resulting from this heat exchange. The first actuating jet 20 will act to entrain'low pressure refrigerant from chamber 38 through the annular passagev 40 and force this refrigerant along with the power fluid into the second nozzle 22. The other nozzles 22 and 26 will operate in asimilar manner-to entrain low, pressure gaseous refrigerant from the chambers 37 and 33, the combined refrigerant- (the original power stream plus theentrained and compressed refrigerant) from the chambers being discharged into the delivery tube 30 against the intermediate pressure existing therein and thence through pipe 35 into the condenser D. The compressing action exerted'on the low pressure refrigerant returned from the evaporator is `obtained at the cost of a partial loss of pressure in the power fluid from the generator, so that the combined refrigerant fiuids delivered into the condenser D will be at an intermediate pressure, somewhat lower than the generator pressure but higher than the low pressure existing in evaporatorH. This type of jet compressor also functions to partially condense the uids passing therethrough so as to A assist-the condenser D which consequently may be smaller than would otherwise be required with a less e'icient type of jet exhauster. It will be noted that a countercurrent flow occurs in this jet exhauster, that is the vapor to' be compressed flows in a direction opposite to that followed by the actuating power fiuid. This tends to give a uniform temperature difference between the gas entering from the evaporator and the actuating power jet. In order to increase the efficiency of the compressor, a pipe line 41 leads from the condensate collector E into one of the low pressure chambers of the jet exhauster, preferably the last chamber 38. This pipe line 41 is provided with a manually controlled valve 42, and a pressure operated valve 43, which latter valve will open to permit a restricted flow of cooled liquid refrigerant from the collector E into the surrounding chambersl of the jet exhauster so as to additionally cool the refrigerant surrounding the nozzles and increase the eiciency of the lso jets. The pressure-operated valve 43 will only open when the intermediate pressure existing in the collector E is sufficiently in excess of the low pressure of the refrigerant returned from the evaporator. While a preferred form of jet exhauster C has been disclosed somewhat in detail, it will be understood that other forms of jet exhausters might be used without departing from certain novel features of the improved refrigerating system as hereinafter claimed.

The condenser D may be either water-cooled or air-cooled, the Aair-cooled type being here shown. This compressor comprises `a plurality of connected pipe loops 44 provided with ns 45 to increase the heat exchange surface. The air-cooled type of condenser may be used when the `temperature of the compressedrefrigerant to be condensed is sufficiently above the highest atmospheric temperature to which the condenser D will be exposed. Obviously, a fan or other suitable means may be used in well-known manner to' enforce a flow of air in contact with the condenser piping. The air or other cooling medium will abstract heat from the refrigerant and condense it, in well known manner, the liquid refrigerant draining through pipe 46 into the condensate collector E. This collector E is simply a receptacle or tank which is entirely closed except for the several inlet and outlet pipe connections hereinbefore and hereinafter described.

A relatively small portion of the condensed liquid refrigerant which is delivered into the collector E flows out through pipe 47, expansion valve G and pipe 48 into the evaporator H to serve as the refrigerating medium. It will be understood. that the evaporator H may be enclosed within the space to be refrigerated, and this evaporator may also enclose a space 49 in which materials from which heat is to be abstracted may be positioned. The space 50 within the evaporator is maintained under a low pressure, (which maybe sub-atmospheric, the pressure depending on the refrigerant used and the evaporator pressure desired), by the exhausting action. The low-pressure vapored refrigerant, the temperature of which may have been somewhat raised by this absorbed heat, is drawn into the main circulating stream by the jet compressor C, and the absorbed heat is dissipated through the condenser D. The expansion valve G controls the rate of flow of liquid refrigerant from the condensate receiver E into the evaporator H, the valve being preferably of the pressure operated type so that there will be no flow of the refrigerant into the evaporator unless the low pressure created in the evaporator by the action of the jet compressor C is sufliciently lower than the intermediate pressure of the condensed refrigerant to insure the refrigerating action taking place in the evaporator. However, other types of expansion valves, such as the float type might be used.

Since the circulating refrigerant is used not only as a refrigerating uid in the evaporator H, but as a power fluid in the jet compressor C, it will be apparent that there will be a considerable quantity of condensed refrigerant at the intermediate pressure delivered into collector E in excess of that required for refrigerating purposes in the evaporator H. This excess liquid refrigerant flows out through pipe 51 provided with one-way valve 52, and is thence delivered back into the generator A. Since a higher pressure exists in the generator A, some device such as F is provided for accomplishing the return of this liquid refrigerant. In a very simple form of the apparatus, if the collection receptacle E is positioned sufficiently high above the generator A, the head of 'liquid in the connecting pipe would be sufficient to discharge the liquid back into the generator by gravity. However, a more compact form of apparatus is desirable, and in thextype of apparatus shown in Fig. 1 a double alternating-receiver device F is employed for assisting the action of gravity in returning the liquid refrigerant into the generator n A simpler, single unit form of receiver is indicated at F in Fig. 3, and this form of device` will rst be described. The liquid refrigerant not required for refrigerating purposes drains out from condensate collector E through pipe 51 into the receiving tank 53, the collected con. Adensate being indicated in this tankat 54. The

oat 55 in tank 53 operates the valve mechanism 56 which automatically opens and closes valves controlling communication with the interior of tank 53 of a pipe 57 leading from the high pressure supply pipe 7, and a pipe 58, provided with control valve 59, leading from the condenser D. As longl as the liquid level 54 within tank 53 is low, communication with high pressure pipe 57 will be cut off,A and the tank will be in open communication through pipe 58 with the condenser so that the interior of receiving tank 53 will be' at the same intermediate pressure asy the condenser D and the condensate collector E. Consequently the liquid refrigerant can-flow freely into tank 53 by gravity. When a sufficient quantity of liquid has collected in the receiver 53, the oat 55 will be so elevated as to operate the valves 56 and cutoff .communication with pipe 58 and open communication with pipe 57 so that generator pressure will be established in the tank 53. The collectedliquid 54 in tank 53 will 'now drain out by gravity through pipe 60 provided with oneway valve 61 and thence into the generator A. When the greater portion' of the liquid 54 has drained out of receiver 53, the valves 56 will be operated to shut off generator pressure through pipe 57 and open pipe 58 so that condenser pres'- sure will again be established in the tank 53, and this receiver will again ll with liquid drained from' the condensate collector E.

The double-unit type of alternating receiver indicated at F in Fig. 1 operates in substantially the same manner as the single unit type just described, but is provided with a pair of similar receiving tanks 53 and 53". TheA valve mechanism 56 is operated in response to the movements of the oats 55 and 55" so that while one of the receivers, for example, 53", is under con-- denser pressure and liquid refrigerant is draining thereinto from the condensate collector E, the other receiver' 53' will be under generator pressure and the refrigerant collected therein will be draining out by gravity into the generator. Consequently there will be a practically continuous flow of refrigerant back into the generator. The two receiving tanks 53 and 53" are provided with separate drain pipes 62 and 63, having oneway valves 64 and 65 respectively opening away from the receiving tanks, both of these pipes discharging into the common drain pipe 60 which leads back into the generator.

In lieu of an alternating receiver device such as indicated at F or F in Figs. 1 and 3, a suitable pumping mechanism may be used to forcethe liquid condensate back into the generator A. A complete refrigerating system including a novel form of pumping device K is shown in Fig. 4. this pump being indicated in enlarged section in Fig. 5. It will be understood that elements of the refrigerating system not here specifically referred to may be the same as already described in connection with Figs. 1 to 3. This pump comprises an upper valve housing 66 which encloses an inlet chamber 67 into which leads the drain pipe 51 extending from the condensate collector E. A valve 68 will automatically be closed when the pressure in chamber 67 exceeds that in pipe 51. A port 69 leads .from inlet lchamber 67 into the pump chamber 70, hereinafter described. The valve housing 66 `also encloses an outlet chamber l71 from which the pipe 60 leads to the generator A. The port 72 leading from pump chamber 70y into the discharge chamber 71 will be closed by Valve 73 when the pressure in pump chamber 70 is less than generator pressure, but will automatically open when the pump chamber is compressedto permit the liquid in this pump cham- Y ber to be forced through port 72, chamber 71 and pipe 60 into the generator A. At this time the valve 68 will automatically close to prevent the .return of liquid through pipe 51 into the collector E. The upper wall of the expansible and contractible pump chamber 70 is formed by the valve plate 66, the remainder of this chamber being enclosed by the flexible bellows diaphragm 74 h'aving a closed lower end 75, and an upper outwardly extending flange `portion `76 which is sealed against valve plate 66 by-the annular I vthe pump chamber through pipe 51. When stem 82 is pushed upwardly and the pump chamberis y sipating means or condenser.

densed fluid has drained into the heating recepcompressed, valve 68 will close and valve 73 will opensc as to permit the liquid collected in pump chamber 70 to beforced out through pipe 60 and thence into the generator A.

A housing 83 is supported on the lower thr aded end portions of bolts 79, and an annular iiexible corrugated diaphragm 84 has its upper outwardly extending flange portion 85-clamped between the upper edge portion of casing 83 and a closure plate -86 held in place by nuts 87 threaded on the bolts 79. The lower end'of the flexible diaphragm 84 is closed by a plate 88 with which the lower end of operating stem 82 is connected. Ports or openings 89 in the closure plate 86 cause the interior of the flexible diaphragm to be under atmospheric pressure at all times. The bottom walls 90 of casing 83 slope downwardly so that liquid condensed within this casing will drain downwardly into a collection receptacle 91. A separate collection receptacle 92 extends downwardly below the receptacle 91, the lower end of receptacle or chamber 92 being surrounded by an electric heater 93 which may receive its current through wires 94 and 95 which may be connected in the operating circuit for heater 2 of the generator. A port 96 connects chamber 92 withthe space 97 within casing 83, this port extending upwardly through a nozzle 98 in the bottom wall 90 so that liquid will not drain through this port into the receptacle 92. A siphon tube 99 is sealed into the wall 1.00 separating the chambers 91 and 92, the siphon including a shorter leg 101 projecting downwardly adjacent the bottom of chamber 91, and a longer leg 102 projecting downwardly into the chamber 92. The expansible and contractible but sealed power chamber comprises the -space 97 beneath the bottom 88 of flexible diaphragm 84, the annular space 103 between the sidesof the diaphragm and the cylindrical walls of casing 83, and thetwo receptacles 91 and 92. A quantity of a suitable volatile iiuid is sealed within this chamber, and when the parts are in substantially the position shown in Fig. 5 the greater portion of this liuid will be condensed and will have drained into the heating chamber 92. 'Ihis power fluid may be water, or ethyl or methyl alcohol, or other suitable volatile fluid, or a mixture of water and one of these fluids. Preferably a suitable insulation such as indicated at 104 is inserted between the lower portion of the heatingr chamber 92 and the upper portion of the casing to minimize the transmission of heatto the upper walls of casing 83 which serve as a heat dis- When the contacle 93 (as shown in Fig. 5) this fluid will be quickly heated and vaporized by the electric heater 93, the gas being forced out through port 96 and filling the power chamber so as to expand this chamber and compress the .flexible diaphragm 84, thus forcing the operating stem 82 upwardly. This will compress .the pump chamber 70 and force out the collected refrigerant through pipe 60 into the generator A. I'he vaporized power iiuid which now lls the power chamber will now be condensed through the dissipation of heat through the walls of casing 83. If desired a water cooling jacket could be provided, but the dissipation of heat to the surrounding atmosphere will ordinarily be suflicientfor this purp se. The condensed power uid will drain dowr into receptacle 91, land the consequent lowering of the pressure in the power chamber will cause the diaphragm 84 to be expanded downwardly by atmospheric pressure entering through ports 89. For the purpose of assisting this down-` ward stroke, a spring 105 may be confined about the stem 82A between vthe lower wall 88 of the diaphragmand a plug ,106 mounted in the cover plate 86. This return stroke will draw the stem 82 downwardly, thus expanding the pump chamber 70 and drawing in another supply of refrigerant through pipe 51 from the condensate collector E. As soon as receptacle 91 has filled with condensed power fluid above the loop 99 of the Siphon, this siphon will act to drain the contents of receptacle 91 into the heating receptacle 92 after which the cycle of operations will be repeated.

In the modified form of pump partially shown in Fig. 6, the siphon 99 i's omitted, and a passage 107 is formed in the wall 100 `separating receptacles 91 and 92 so that the liquid will drain through this passage when forced from the receptacle 91. A plunger 108 is suspended by stem 109 from the bottom of the lower wall 88 of the iiexible diaphragm 84. As this diaphragm expands downwardly, the plunger 108 will be forced into the receptacle 91 so as to displace the collected condensate therein and force it out through passage 107 into the heating receptacle 92. The cycle of operations is substantially the same as described in connection with Fig. 5.

In the modification shown in Fig. 7, the heating chamber 92' is enlarged so as to be positioned partially beneath the collection' receptacle 91', there being a drain passage 110 extending from the bottom of receptaclel 91' into the heating chamber 92'. The valve 111 consists of a bar of thermostatic material, preferably a bi-metallic thermostat, which when cold will curve upwardly as shown in solid lines so as to open the passage 110. When heated this thermostatic valve will warp downwardly to the position shown in dotted lines so as to close the drain passage 110. A second similar thermostat 112 may be positioned on one of the side walls 83 of the condensing chamber. When this thermostat 112 is in the cold position shown in solid lines it will hold the movable switch arm 113 with which one oi the power leads 94 is connected againstA a relatively xed switch arm 114 which is connected through wire 115 with one of the terminals of;heater 93. When the thermostat 112 is heated it will straighten out to the dotted line position thus permitting the spring switch arm 113 to move inwardly and separate the switch contacts thus breaking the heater circuit.

The position of parts shown in Fig. 7 corresponds to the position shown in Figs. 5 and 6. The heating circuit is now completed and the liquid in chamber 92 will be quickly volatilized and forced out into the power chamber. 'I'he two thermostats will be heated and will straighten out so that thermostatic valve 111 will close the passage 110 in the bottom of drain chamber, 91', and the thermostat 112 will permit the switch to open and break the heating circuit. As the vapor cools and condenses, it will drain d own into chamber 91', and thecooled condensate will lower`the temperature of thermostatic valve 111 so that this valve will warp upwardly to the solid line position and permit the condensate to drain back into heating chamber 92'. As the walls of casing 83 cool, the thermostat 112 will warp outwardly so as to close the switch and again complete the heating circuit. The cycle of operations of the pump is substantially the same as in the other modifications already described.

Returning now to the operation of the assembled refrigerating apparatus, when the operation is started the generator A will vaporize the collected liquid refrigerant 1 until a sufficient pressure has been built up in the generator and supply pipe 7 to cause the valve B to open, whereupon the jet compressor C will begin functioning to lower the pressure in the evaporator H. The refrigerant passing through condenser D will be liquefied and drain into collector E, a portion of this refrigerant passing through expansion valve G when a sufficient difference of pressure has been establish between the pressure of the condensed refrigerant and the low pressure created in the evaporator H. 'Ihe evaporator H willv then begin to function to absorb heat and the refrigerating action will be established. When a sufficiently low temperature has been established by evapo.

rator H, the thermostat 5 will function to temporarily shut off the heater 2' in the generator. 'I'he pressure operated safety device 6 will also operate to cut out the heater 2 in case an eX- cessively high pressure should be developed in the generator. If at any time the generator pressure falls below a proper operating pressure, the differential-pressure operated valve B will close to temporarily stop the operation of compressor C. The alternating-receiver device F or F', or the pump K if used, will function'automatically to return the excess refrigerant collected in receptacle E back into the generator A so that the cycle of operations will be substantially continuous.

It will be noted that there are very few moving parts in this apparatus, and the entire circulating system may be sealed. If a suitable refrigerant is used so that the cycle of operating pressures is less than atmospheric, there will be no tendency for outward leaks, and the hazards resulting from leaking refrigerant is minimized.

If desired, this equipment could be multistaged by using a plurality of :jet exhausters and condensers in series in an obvious manner.

I claim:

1. The method of refrigerating in which refrigerant is circulated through a closed system, consisting in heating the refrigerant in a closed generating space to-vaporize it under relatively high pressure, passing the high pressure vaporized refrigerant through a jet compressor towithdraw low pressure vaporized refrigerant from an evaporating space and compress it, condensing the vaporized refrigerant from the compressor at an intermediate pressure, returning a portion of the condensed refrigerant to the low pressure evaporating space and the remainder tothe generating space, and maintaining a predetermined minimum pressure difference between the high pressure vaporized refrigerant and the intermediate pressure condensed refrigerant.

2. The method of refrigerating in which refrigerant .is circulated through a closed system, consisting in heating the refrigerant `in a closed generating space to vaporize it under relatively high pressure, passing the high pressure vaporized refrigerant through an exhausting apparatus tov withdraw low pressure vaporized refrigerant from an evaporating space and compress it, condensing thevaporized refrigerant from the exhauster at an intermediate pressure, returning a portion of the condensed refrigerant to the low-pressure pressure vaporized refrigerant and the intermediate pressure' condensed refrigerant.

3. The method of refrigeranting in which refrigerant is circulated through a closed system, consisting in heating the refrigerant in a closed generating space to vaporize it under relatively high pressure, passing the high pressure vaporized refrigerant througha jet compressorjto withdraw low pressure vaporized refrigerant from an evaporating space and compress it, condensing the vaporized refrigerant from the compressor at an intermediate pressure, returning a portion of the condensed refrigerant to the low pressure evaporating space, conducting the remainder of the condensed refrigerant to a collection space, and intermittently establishing generator pressure in this collection space and returning the condensed refrigerant therein by gravity to the generating space.

4. The method of refrigerating in which refrigerant is circulated through a closed system, consisting in heating the refrigerant in a closed generating space to vaporize it under relatively high pressure, passing the high pressure vaporized refrigerant through a jet compressor to withdraw low pressure vaporized refrigerant from an evaporating space and compress it, condensing the vaporized refrigerant from the compressor at an intermediate pressure, returning a portion of the condensed refrigerant to the low pressure evaporating space, utilizing pressure from the-generating space to return the remainder of the condensed refrigerant to the generating space, and maintaining a predetermined minimum pressure vdifference between the high pressure vaporized refrigerant and the intermediate pressure condensed refrigerant.

5. The method.of refrigerating in which refrigerant is circulated through a closed system,

consisting in heating the refrigerant in a closed L generating space to vaporize it under relatively high pressure, passing the high pressure vaporized refrigerant through a jet compressor to withdraw low pressure vaporized refrigerant from an evaporating space and compress it, condensing the vaporized refrigerant from the compressor at an intermediate pressure, returning a portion of the condensedrefrigerant to the low pressure space. forcing the remainder of the condensed refrigerant back into the generating space, and maintaining a predetermined minimum pressure difference between the high pressure vaporized refrigerant and the intermediate pressure condensed refrigerant.

6. The method of refrigerating in which refrigerant is circulated through a closed system, consisting in heating the refrigerant in a closed generating space to vaporize it under relatively high pressure, passing the high pressure vaporized refrigerant lthrough a jet compressor to withdraw low pressure vaporized refrigerant from an evaporating space and compress it, condensing the vaporized refrigerant from the compressor at an intermediate pressure, returning a portion of the condensed refrigerant to the low pressure evaporating space, pumping the remainder of the condensed refrigerant back into the generating spacel by the alternate vaporization and condensation of a liquid hermetically sealed in a container, and maintaining a predetermined Vminimum pressure difference between the high,4 pressure vaporized refrigerant and the intermediate pressure condensed refrigerant.

7. The method. of refrigerating in which refrigerant is circulated through a closed system,

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consisting in heating the refrigerant in a closed generating space to vaporize it under relatively high pressure, passing the high pressure vaporized refrigerant through a jet compressor towithdraw low pressure vaporized refrigerant from an evaporating space and compress it, condensing the vaporized refrigerant from the compressor at an intermediate pressure, returning a controlled portion of the condensed refrigerant to the evaporating space, returning another controlled portion of the condensed refrigerant to the low pressure portion of the compressor, and returning the remainder of the condensed refrigerant to the generating `space.

8. The method of refrigerating in' which the refrigerant is circulated through'a closed system,

consisting in heating the refrigerant in a closedv generating space to vaporize it under relatively high pressure, passing the high pressure vaporized refrigerant through a jet compressor to withdraw low pressure vaporized refrigerant from an evaporating space and compress it, condensing the vaporized refrigerant from the compressor at an intermediate pressure, returning a controlled portion of the condensed refrigerant to the evaporating space, returning the remainder of the condensed refrigerant to the generating space, maintaining a predetermined minimum pressure difference between the high pressure vaporized refrigerant and the intermediate pressure condensed refrigerant, and controlling the application of heatl in the generating space in accordance with temperature conditions adjacent the evaporator.

9. The method of refrigerating in which refrigerant is circulated through a closed system, consisting in heating the refrigerant in a closed generating space to vaporize it under relatively high pressure, passing the high pressure vaporized refrigerant through a jet compressorto withdraw low pressure vaporized refrigerant from an evaporating space and compress it, condensing the,

vaporized refrigerant from the compressor at an intermediate pressure, returning a controlled portion of the condensed refrigerant to the evaporating space, returning the remainder of the condensed refrigerant to the generating space, maintaining a predetermined minimum pressure difference between the high pressure vaporized refrigerant and the intermediate pressure condensed refrigerant, and controlling the application of heat in the generatingl space to limitthel maximum pressure produced therein.

10. A refrigerating apparatus comprising a generator, a jet compressor, a .condenser and a con densate collector connected' in a closed cycle in the order named, the generator including means for heating liquid refrigerant to vaporize the same under relatively high pressure, automatically actuated valve means for controlling the flow of vaporized refrigerant from the generator to the jet compressor so as to maintain a predetermined minimum pressure differential between the high pressure vaporized refrigerant and the intermediate pressure ofthe condensed refrigerant in the collector, an evaporator, means for permitting a controlled flow of a portion of the condensed refrigerant fromithe collector into the evaporator, an exhaust conduit leading from the evaporator to the jet compressor, the jet compressor operating to maintain a low pressure inthe evaporator and to withdraw low pressure vaporized refrigerant from the evaporator and introduce it into the refrigerant stream passing into the condenser, and means positioned in the main closed cycle between the collector and generator for returning the remainder of the condensed refrigerant into the generator.

1l. A refrigerating apparatus comprising a genfrigerant from the collector into the evaporator,

van exhaust conduit leading from the evaporator to the jet compressor, the jet compressor operating to maintain a low pressure in the evaporator and to withdraw low pressure vaporized refrigerant from the evaporator and introduce it into the refrigerant stream passing into the condenser, means positioned in the main closed cycle between the collector and generator for-returning the remainder of the condensed refrigerant into the generator, said last mentioned means comprising a receiver into which thecondensate drains from the collector, and means for intermittently establishing generator pressure in this receiver so that the condensate therein will drain by gravity into the generator.'

12. A refrigerating apparatus comprising a generator, a jet compressor, `a condenser and a condensate collector connected in a closed cycle in the order named, the generator including-- lthe evaporator to the jet compressor, the jet compressor operating to maintain a low pressure in the evaporator and to withdraw low pressure vaporized refrigerant from the evaporator and introduce. it into the refrigerant stream passing into the condenser, means positioned in the main lili Lal

closed cycle between the collector and generator for returning the remainder of the condensed refrigerant into the generator, said last mentioned means comprising a pair of receivers into which the condensate alternatively draws from the collector, and means for alternatively establishing generator pressure in these receivers so that the condensate will drain therefrom by gravity into the generator.

13. A refrigerating apparatus comprising agenerator, a jet compressor, a condenser and a condensate collector connected in a closed cycle in the order named, the generator including means for heating liquid refrigerant to vaporiz'e l the same under relatively high pressure, automatically actuated valve means for controlling the ow of vaporized refrigerant from ,the generator tothe jet compressor so as to maintain a predetermined minimum pressure differential between the high pressure vaporized refrigerant lull andthe intermediate pressure of the condensed refrigerant in the collector, an evaporator, means for permitting a controlled flow of a portion of the condensed refrigerant from the collector into the evaporator, ari` exhaust conduit leading from the evaporator to the jet compressor, the jet compressor operating to maintain a. low pressure in the evaporator and to withdraw low pressure vaporized refrigerant from the evaporator ,and introduce it into the refrigerant stream passing into the condensor, and a pump positioned in the main closed cycle between the collector and generator for returning the remainder of the condensed refrigerant to the generator, said pump comprising a pump chamber, inlet and outlet valves communicating with the pump chamber, a closed power chamber, a. movable power member separating the pump chamber and power chamber, a fluid hermetically sealed in the power chamber, and means for alternatively vaporizing and condensing the fluid in the power chamber to'produce movements of the power member.

14. A refrigerating apparatus comprising a generator, a jet compressor, a condenser and a condensate collector connected in a closed cycle in the order named, the generator including means for heating liquid refrigerant to-vaporize the same under relatively high pressure, automatically actuated valve meansforcontrolling the flow of vaporized refrigerant from the generator to the jet compressor so as to maintain a predetermined minimum pressure differential between the high pressure vaporized refrigerant and the intermediate pressure of the condensed refrigerant in the collector, an evaporator, means for permitting a controlled flow of a portion of the condensed refrigerant from the collector into the evaporator, an exhaust conduit 'leading from theV evaporator to the jet compressor, the jet compressor operating to maintain a low pressure in the evaporator and to withdraw low pressure vaporized refrigerant from the eiraporator and introduce it into the refrigerant stream passing into the condenser, means positioned in the main closed cycle between the collector and generator for returning the remainder of the condensed refrigerant into the generator, and means for temporarily rendering ,the generator heating means inoperative when a predetermined maximum pressure is established in the generator. r

15. A refrigerating apparatus comprising a generator, a jet compressor, a condenser-and a condensate collector connected in aclosed cycle in the order named, the generator including means for heating liquid refrigerant to vaporize `the same under relatively high pressure, automatically actuated valve means for controlling the flow of vaporized refrigerant from the generator t the jet compressor so as to maintain a predetermined minimum pressure differential between the high pressure vaporized refrigerant and the intermediate pressure of the condensed refrigerant in the collector, an evaporator, means for permitting a controlled ow of a portion of the condensed refrigerant from the collector into the evaporator, an exhaust conduit leading from the evaporator to the jet compressor, the jet compressor operating to maintain a low pressure in the evaporator and to Withdraw low pressure vaporized refrigerant from the evaporator and introduce it into the refrigerant stream passing into the condenser, means positioned in the main closed cycle between the collector and generator for returning the remainder of the condensed refrigerant into the generator, and means for temporarily rendering the generator heating means inoperative when a predetermined minimum temperature is established in the evaporator.

16. A refrigerating apparatus comprising a generator, a jet exhauster, a condenser and a condensate collector connected in a closed cycle in the order named, the generator including means for heating liquid refrigerant to vaporize the same under relatively high pressure, automatically actuated valve means for controlling the flow of vaporized refrigerant from the generator to the jet exhauster so as to maintain a predetermined minimum pressure differential between the high pressure vaporized refrigerant and the intermediate pressure of the condensed refrigerant in the collector, an evaporator, means for permitting a,"controlled flow of condensed refrigerant from the collector into the evaporator, the jet exhauster comprising a receiving space for low pressure refrigerant and means for lprojecting a jet of the high pressure refrigerant from the generator therethrough, an exhaust conduit leading from the evaporator to the receiving space of the j et exhauster, means for permitting a controlled flow of condensate'from the condensate collector into the receiving space jof the jet exhauster, and means positioned in the main closedw cycle between the condensate receiver and the generator for returning the remainder ofthe condensed refrigerant into taie generator.

y DAVID N. CROSTHWAIT, JR. 

